Lamp holder



Dec. 25, 1956 E. G. GODDARD 2,775,743

LAMP HOLDER Filed om. '7, 195:5- 2 sheets-sheet 1 Dec. 25, 1956 A E. G. GODDARD 2,775,743

LAMP HOLDER Filed Oct. '7, 1953 2 Sheets-Sheet 2 F15 4 FE E 4l 44 I /fz /0 9 f5 /ff i554 f5 United States Patent() 2,775,743 LAMP HOLDER Edwin G. Goddard, Lombard, Ill.

Application October 7, 1953, Serial No. 384,692

Claims. (Cl. 339-52) This invention relates -to an improved `lamp holder for lluorescent lamp tubes.

LA lamp holder is :a separately manufactured unit which is customarily sold to iix-ture manufacturers -for incorporation into a iluorescent lamp ixlture. Dhe iixture includes the ballast, a reflector, and such other structural parts and `as may be necessary or desirable.

The present invention relates to` a lamp holder of the -type which comprises one formore supporting devices for supporting one end of one 0r more lamp tubes, and a box in `which the supporting device or devices are located.

The supporting device also includes means for making electrical contact with the terminal of the tube end, :and in some instances, this contact means includes what is known' 'as fa pr' ary disconnect, as explained hereinafter.

The box serves as a receptacle to accommodate leads from the various supporting devices; it is generally a totally enclosed receptacle having circular openings in one wall located :at a point adjacent the various tubes supporting devices so that the tube ends may be received within the circular openings.

LIt is an .object of .this invention to provide for la lamp holder of the type indicated, an improved tube supporting device which is lfabricated [from 'a minimum number of parts, the general :arrangement of which is of standard construction, so Ithat the particular supporting device can be readily adapted to support either :a single prong tube or a two-prong tube, Aat either the primary disconnect end lor the high voltage end.

A |further object of the invention is to provide improved lamp holding means which permits a tube to be resiliently supported yat both of its yends to the end that the tube may Ibe maintained in centered position with respect .to the two lamp holders lwhich .support it, Aand also to the end that mechanical shocks will not be transmitted to the tube, the resilient means also serving to maintain good electrical contact between the tube terminal and the contact members.

A further object of the present invention is to provide a supporting device which includes .a resiliently mounted supporting member, together with spring means for urging the same into its operative position, the .arrangement being such that the spring means is not a lcurrent carrying part.

)In this connection, I have provided -a tube supporting device which comprises a U-shaped frame `and :a supporting member of general disc shape which is slidably mounted on the legs of the U-shaped frame. Springs are provided which surround each of the legs of the U-shaped [trame to urge the disc-shaped Isupporting member torwardly. 'Thus, fa iloating tube support is provided. Electrical connections are made by means of llexible leads which extend trom contact members, carried `by the supporting member, through a suitable opening in the receptacle. 'Ihe springs are loosely disposed around the legs and the supporting member loosely engages the legs'so that neither the springs nor the supporting member are subject to binding.

A still .further object of the present invention is to provide an improved supporting member having a dead liront, this term referring to a construction in which no v current-carrying parts are exposed, thereby avoiding shock to the operator during the installationor removal of a tube.

According to this aspect :of my invention, the supporting mem-ber is a composite member or contact assembly made up of two discs of suitable insulating material, the contact members being sandwiched between these insulating members in such a manner that they are locked in a deinite position. y

`Still -another object of the present invention is to provide, for a primary disconnect tube supporting device, an improved resilient contact construction 'which is charac- .terized by improved resilient action.

It is .a still further lobject ofthe present invention to provide 1an improved 'tube -supporting device which is structurally independent ofthe box, to the end that the supporting device can be located at any desired point in the box. Thus, a standard type of supporting device can be provided `which is suitable for use in different types of tube holders :which are designed for holding varying numbers of tubes in varying spaced relationships.

`Other objects, features 4and .advantages will become apparent 'as the description proceeds.

With refe-rence now to .the drawings in which like reference numerals designate like parts:

4Fig. l is a perspective yview of an installation comprising two iluorescent lamp tubes and lamp holders tor supporting the same, the lamp holders .embodying my invention; p

Fig. 2 is an elevation of one of the lamp holders shown in Fig. l, the cover being removed to show the supporting devices;

Fig. 3 is a bottom plan view of the lamp holder shown in fFig. 2; t

Fig 4 is a vertical section taken along line I4-44 of Fig. 2; but also showing the cover;

Fig. `5 is -a section taken along 'line 5-5 of iFig. 4;

Fig. 6 is a vertical section `taken valong line 6-6 of Fig. 5;

tFig. 7 is an enlarged perspective view of one of the contact members;

Fig. 8 is a view showing the front surface of the iront plate of a modied type -of contact assembly;

lFig. 9 is a rear view of the backing plate of said modiiication, the contact members being eliminated for purpose of clarity; .and

Fig. l() is a sectional view similar to Fig. 6, `and taken Ialong line l0-110 of Fig. 9.

In lFig. l, the reference numeral 10 designates ya plurality of lluorescent` lamp tubes which yare supported at their ends by lamp holders :111. `As shown in lFig-s. 2 4, each lamp holder comprises a base 12 having a horizontal ywall 1'3, :which is bere shown a-s the -t-op wall, although the lamp holder could be inverted in some installations, -and a vertical rear wall114.

The lamp holder lalso includes a cover 15 having a front -wall k16 and a horizontal wall 17, together with suitable end walls as shown in IFig. l. The cover may be suitably secured .to the base :by means of screws 44 which .are threaded into .the ange yon lthe base 112.

The lfront wall |16 of the cover is :provided with one or more circular openings 4-3 to receive the terminal of a lamp tube 10.

The lamp holder includes one or more tube supporting devices 18 which are vmounted within the receptacle 12-15 at a point immediately behind the openings 43. The tube supporting devices 18 comprise a contact assembly, designated generally by the reference numeral 19, and a bracket assembly including a U-shaped bracket 2G and springs 23, to provide a resilient mounting for the contact assembly.

The U-shaped bracket 20, as shown in` Fig. 4, is secured to the rear wall 14 of the base 12 by rivetsZl. The contact assembly 19 is provided with slots 24 through which the legs of the bracket extend, the ends 22 of each leg being bent over to conline` the contact assembly on the bracket. Thus, the contact assembly, is slidably mounted on the bracket 20. Springs 23 surround each of the legs of the `bracket and urge the contact assembly 19 forwardly against the bent ends 22.

Thus, the contact assembly may be displaced rearwardly against the bias of springs 23, and this displacement is effected each time a lamp tube is removed or inserted, since the over-all length of the tube is greater than the distance between the walls 16 of the spaced lamp holders 11.

Heretofore, as shown in my prior Patent No. 2,620,372, and in Kulka Patent No. 2,464,643, it has been the practice to provide in a-particular installation, two lamp holders which are structurallydifferent from each other, and only one of which provides a full oating, or resilient mounting. This is for the reason that installations of this type customarily embody a primary disconnect, which term refers to anarrangement whereby one terminal of cach tube engages and completes a series circuit between two separate contact members, the contact members being connected in series circuit with the primary of an auto-transformer connected ballast. Thus, the tube supporting device requires two separate leads, and for this reason it has ybeen ditiicult to mount the primary disconnect tube supporting device resiliently for the reason that the spring that imparts resilience is customarily a current carrying part.

According to the present invention, the springs 23 are not current carrying parts, with the result that identical tube supporting devices can be used at each end of the tube, thus providing a resilient mounting at both ends. Since some types of tubes vary in length by as much as plus or minus one-eighth of an inch with respect to a standard length, it `will be seen that a resilient mounting at both ends is advantageous since the separate tubes will each be centered with respect to the lamp holders, irrespective of variations in length.

The construction of the contact assembly 19, whichv is shown in Figs. 2 and 5 to 7, .will now be-described. Each contact assembly includes a face plate 25 and a backing plate 26, both of which are made of suitable insulating material, such as a laminated plastic. The face plate is provided with a circular aperture 27 having a diameter sufficient to loosely receive or accommodate the prong of a single prong tube terminal. The lbacking plate is provided with an aligned circular aperture 28 of somewhat larger diameter, as shown in Fig. 6. The backing plate 26 is also provided with slots 29 which are spaced from the circular aperture 28 at opposite sides thereof. The two plates 25 and 26 are secured to each other by suitable rivets 30.

Disposed between the two plates are two substantially identical Contact members 31. As shown in Fig. 7, the contact member is of generally U-shape, one end being bent rearwardly to form a prong contacting flange 32. The other end is bent rearwardly to form an angularly disposed portion 33; the portions 33 and 32 are connected by a flat connecting portion 34. Portion 33 serves as a conductor terminal and in this connection it is provided with a notch 36 which facilitates the welding of a conductor 37 thereto. The stripped end of a conductor 37 is preferably brazed or spot welded to the front surface of the connecting portion 34, the notch 36 serving to accommodate the bared end. However, the conductor may be soldered directly to the terminal 33 if desired.

The contact member 31 may be made of comparatively heavy copper or brass sheet or strip stock so that the contact flange 32 will have sufficient resilience to provide good electrical contact with the prong of a tube terminal. The angular disposition of the portion 33 is preferably such that it will take up any clearance between the contact member 31 and the walls of the slot 29, to the end that the contact member will not move back and forth between the plates 25 and 26.

Thus, in the present arrangement, since the plates are secured to each other, and the connecting portion 34 is tightly conlined between the two plates 25 and 26, the contact members are securely held in the desired position without the use of additional fastening means. The front surface of the face plate 25 therefore presents a dead front, or a completely insulated surface, the only .projecting parts being the rivets 30 which are not in contact with any current carrying parts. Furthermore, the contact flanges 32 are disposed well beneath the surface of the face plate 25 where they are not likely to be contacted by the fingers of the operator. The bracketassembly 20-23 is also well insulated from the currentcarrying parts 31.

Where the particular'tube supporting device 19` is to embody a primary disconnect, two conductors 37 and 38 are provided, one being soldered to one conductor terminal 35 and the other conductor being soldered to the terminal 35 of the opposite contact member. Where the particular tube lsupporting device is to engage the high voltage end of the'tube, then only one of the contact members 31 is connected to a conductor,I and this conductor will be the high voltage lead of the ballast.

To the rear wall 14 of the base is secured, as by a rivet 41, a plate or sheet 39"of insulating material, and a strain relieving clip 40, also made of insulating material. The conductors 37 and 38 pass through the clip 40 and out of the receptacle through a suitable opening 42 formed in the horizontal wall 13. Similar conductors 37 and 38' pass through the clip 40 and extend to the other tube supporting device or devices. In the event that one or both of the tube support devices shown are for the high voltage terminal of the tube, then only one conductor will extend from that tube supporting device, as pointed out above.

The contact assembly may be slightly modified to accommodate a two prong tube as shown in Figs. 8-10, the primed reference numerals referring to the corresponding parts in Figs. 2-7. Here, the face plate 25 is provided with two circular apertures 50 and 51adapted to receive the prongs of a two prong tube terminal. The backing plate is provided with two pairs of openings 53, 54 and 55, 56. Openings 53 and 56 each correspond to the slots 29 shown in Fig. 5, since they are adapted to receive the terminal portions of contact members 57 and 58, respectively.

Each of the openings 54 and SS'are adapted to overlie the openings 51 and 50', respectively, so as to receive the terminal prongs. However, since the prongs of a two prong tube are substantially of smaller diameter than the diameter of a one prong tube it is necessary to impart to the opening 54 and 55 an elongate, or slot-like shape, so that these openings will also accommodate the prong contacting anges of each of the contact members 57 and 58, respectively.

The relationship of the parts as assembled is more clearly shown in Fig. 10.

The primary disconnect feature is not customarily embodied in a lamp holder fora two prong tube; hence, the two prong contact assembly herein shown requires just one conductor for each prong.

To summarize the operation, after thevlamp lholders 11 have been suitably mounted on a fixture orzother supf porting means, kthe tubes 10 are inserted. This is done` by inserting one end of a tube through its opening 16 in one of the lamp holders in such .a manner that the prong of the tube enters into the apertures 27 'and` 28 and is engaged by contact members 31. Continued longitudinal movement of the tube will cause the contact assembly 19 to be urged backwardly against the bias of springs 23 so as to permit the opposite end of the tube to clear the receptacle cover 15 and be inserted through corresponding opening 43 so that the prong operatively engages the contact assembly 19 of the other lamp holder. When the tube is released, then the springs will cause the re spective contact assemblies to adjust themselves so that the tube is centered.

Insertion of the tube prong into that one of the contact assemblies that has two conductors will serve to establish the primary circuit; similarly removal of the tube prong from that contact assembly will break the primary circuit.

One of the main advantages of the present invention is that both lamp holders may be identical to each other, so far as structure is concerned, the distinction between a high voltage lamp holder or tube supporting device and the primary diconnect lamp holder or tube supporting device being merely that theglatter requires an extra conductor.

This identity of construction materially simplifies manufacturing and inventory problems.

Similarly, since the tube supporting devices 18 are identical to each other and are structurally independent of the receptacle, much greater latitude of design is obtained, since the number of tube supporting devices per lamp holder and the spacing between the two supporting devices aiects only the design of the base 12 and cover 15.

It will be observed in Figs. and 6 that the aperture 28 is larger than the aperture 27 so that clearance is provided to accommodate the bend between the contact flange 32 and the connecting portion 34. Without this clearance the contact flange would occupy, or obstruct a much larger proportion of the area of the circular aperture 27 and it would not be resilient. With the arrangement shown herein, the aperture 27 may be dimensioned to closely approximate the diameter of the tube terminal so that the tube is actually engaged and supported by the insulating plate 25 at the edge of the aperture 27. The manner in which the resilient contact flanges 32 are thus disposed with respect to the edges of the apertures 27 and 28 thus insures that flexure will take place at the bend to provide good electrical contact.

The identity of construction contributes to uniformity of xture appearance, and also permits the tube to be inserted first either -at the primary disconnect end, or at the low voltage end.

The present arrangement renders it possible to so space the two lamp holders that the terminal caps of the tubes will be wholly received within the openings 43 so that just the glass wall of the lamp will be exposed to the eye, as contrasted with the present practice wherein at least one and sometimes both of the terminal caps are exposed to view.

Although only preferred embodiments of my invention have been shown and described herein, it is understood that various modications and changes may be made in the construction without departing from the spirit ofV my invention as pointed out in the appended claims.

I claim:

1. A lamp holder comprising a base, a cover cooperating with said base to form an enclosure, said cover providing the front wall of said enclosure and said base providing the back wall thereof, and a structurally independent tube supporting device mounted within said enclosure, said tube supporting device including a Ushaped bracket having two legs and a connecting portion, means securing said connecting portion to said base, a plate of insulating material slidably mounted on the legs of said bracket, a spring surrounding each of said legs for urging said plate forwardly toward the ends of said legs, said plate being formedV with a centrally disposed'circular' said tube supporting device including a U-shaped bracket having two legs and a connecting portion, means for securing saidpconnecting portion to said base, a contact assembly slidably mounted on the legs of said bracket, a spring surrounding each of said legs for urging said contact assembly forwardly toward the ends of said legs, the ends of said legs being bent over to provide a stop for limiting forward motion of said contact assembly,

said contact assembly comprising means for engaging a tube prong in support-ing relationship and for making electrical contact therewith, and a cover mounted on said base and cooperating with said base to form an enclosure, said cover including a front wall overlying said contact assembly and said front wall being provided with an opening opposite said contact assembly.

3. A lamp holder comprising a base and a tube supporting device mounted on said base, said tube supporting device including a contact assembly and means for resiliently mounting same for bodily displacement, said contact assembly comprising a pair of plates of insulating material secured to each other in face to face engagement, said plates being formed with centrally disposed aligned openings, and a U-shaped contact member having a connecting portion conned between said plates and two legs, one of said legs extending into said openings and projecting rearwardly through the same to provide a contact tiange, the other of said legs passing through one of said plates to provide a conductor terminal whereby said contact member may be energized, said insulating plates serving to insulate said cont-act member from said resilient mounting means.

4. A lamp holder comprising a base and a structurally independent tube supporting device mounted on said base, said tube supporting device including a U-shaped bracket having two legs, a contact assembly slidably mounted on the legs of said bracket, a spring surrounding each of said legs for urging said contact assembly forwardly towards the ends of said legs, said contact assembly comprising a pair of plates of insulating material having openings formed therein to receive said legs, and being riveted to each other in face to face engagement, said plates being formed with centrally disposed openings, and a pair of contact members each having a body portion confined between said plates and each having a contact ange extending into said openings and projecting rearwardly through the same, the outer ends of said contact members passing through one of said plates to provide conductor terminals whereby one or both of said contact members may be energized, said contact members being spaced from said first-mentioned openings so that said bracket legs will be insulated from said contact members.

5. A lamp holder comprising a base member and a tube supporting device mounted on said base, said tube supporting device including two mounting posts projecting forwardly from a portion of said base member, a contact assembly slidably mounted on said posts, a spring surrounding each of said posts for urging said contact assembly forwardly toward the ends of said posts, said contact assembly comprising a pair of plates of insulating material having openings formed therein to receive said posts, and being arranged in face to face engagement, said plates being formed with centrally disposed circular openings and the rearward plate being provided with parallel slots one on each side of said circular opening, ,a pair of contact members each having a body portion coniined between said plates and each having a contact flange extending into said openings and projecting rearwardly through the same, the outer ends of said contact members each passing through one of said slots to provide conductor terminals whereby one or both of said contact members may be energized, said contact members beingv spaced from said hust-mentioned openings so that said posts will be insulated from said contact members, and means securing said plates to each other so as to maintain said contact anges in said opening and said outer ends in said slots Without crimping.

References Cited in the le of this patent UNITED STATES PATENTS 2,032,979 Fischer Mar. 3, 1936 8 Mathern May 6, Sparling June 2, McCann Nov. 22, Barre Oct. 20,

FOREIGN PATENTS Great Britain Mar. 20, 

